The construction of a modern house requires careful planning and attention to detail for all types of electrical connections such as AC power lines, outlets, switches, phone lines, cables, etc., that are currently needed or will be needed in the future. The electrical wiring in a modern house is typically hidden in the walls, and it is necessary to lay all the electrical connection wires inside the walls during the construction of the walls.
Generally, the wiring for the conventional AC power connections are governed by fairly stringent national standards and construction codes, due to the relatively high voltages and currents involved. The AC power wires are typically strung inside a network of steel pipes and junction boxes disposed in the walls, which supports and protects the relatively thick and stiff AC wires.
In contrast, generally much less attention is given to the electrical wiring for low-voltage appliances, such as telephones and doorbells, that operate on low voltages and low currents. The wiring for such low voltage appliances is separate from the AC power wiring, and typically the low voltage wires are simply strung through the interior of the walls to predefined locations without special provisions for stress relief or extra protection of the wires.
An example of low-voltage wiring is the wiring for a doorbell button. A doorbell button is typically a push-button type electrical switch mounted on a wall adjacent the front door of the house and wired to a doorbell chime inside the house. Since the doorbell button is mounted on the exterior of the house, the doorbell wire has to be passed through the wall in order to make connection to the doorbell button. The doorbell wire typically has relatively thin conductors and relatively thin and fragile insulation as compared to the AC power wires.
It is common that the electrical connection to the doorbell button has to be repaired every five to ten years. The common causes of faulty connection to the doorbell button are oxidation of the conductors and broken insulation on the wire. The conductors of the wire at the connection to the doorbell button tend to oxidize over time and form bad contacts. The insulation on the wire adjacent the doorbell button also tends to deteriorate over time. The deterioration of the wire insulation eventually causes the conductors to be exposed, and the exposed conductors may come into contact with each other to form a short circuit and burn out the door chime.
In either case, the deteriorated end section of the wire has to be cut off and a new connection to the doorbell button has to be made. However, a frequently encountered problem is that after the damaged end section of the wire is removed, there is not enough wire left for making the new connection. This problem is especially significant if the house has brick walls or a brick facade, because in such a case the doorbell wire is typically mortared in the wall between bricks, with only a short end section of the wire extending out of the wall for connection to the doorbell button. If the exposed end section of the wire becomes too short for making a new connection, a portion of the brick wall may have to be removed in order to redo the wiring.
U.S. Pat. No. 3,941,915 to Boghosian discloses a doorbell switch receptacle which has a tubular body with a removable cap on one end and a mounting plate on the other end. The tubular body serves as a conduit for the doorbell wire to pass through the wooden wall on which the doorbell button is mounted. During the construction of the wall, the cap is used as a tie-off point for locating the end of the wire. After the wall is completed, the cap is removed from the end of the tube, and the doorbell button is mounted on the wall with the body of the switch inserted into that end of the tube. Although the doorbell switch receptacle is useful in that it serves as an interface between the doorbell button and the wall on which the button is mounted, it does not provide a solution to the problem of not having sufficient doorbell wire for future repairs as described above.